Carburetor



Nov. 15, 1927. 1,649,260

F. SCHOENWOLF CARBURETOR Filed Oct. 14, 1922 Patented Nov. 15, 1927.

UNITED STATES N `115411260 PATENT oFFIcE.,

FRED SCHOENWOLF, 0F CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0

CURTIS B. CAMP, TRUSTEE, OF OAK PARK, ILLINOIS. A

CARBURETOR.

Application filed October 14, 1922: Serial No. 594,521.

This invention relates to carburetors for lifting fuel from 'a low'level supply to a position adjacent to an internal combustion engine, and there mixing .the fuel with air to form a combustible mixture.

'llhe carburetor of my invention utilizes a small Venturi tube acting to enhance the suction'of .the carburetor mixing chamber for fuel lifting purposes. The advantages gained from carburetors having meansfor enhancing the mixing chamber suction for lifting fuel to a Heat chamber, or other reservoir, are fully setl forth in the patent to Milford Gr. Chandler, No.1 1,37 0,919, dated March 8, 1921, and need not be repeated here.

My carburetor is use upon an automo the invention lis to simplify and lighten the structure of carburetors used for this purpose so that there will be few parts liable to become disordered through vibration and wear. l

Another object of the invention is to proprimarily intended for vide a construction in the manufacture of which considerable tolerance of .dimensions may be allowed without interferingnvith the successful operation of the device. The invention comprises, primarily, a movable sleeve shaped internally like the discharge end of a Venturi tube, this sleeve serving both for providing a variable restriction to the admission of,` air to the mixing chamber of the carburetor, and for creating avelocit suction upon the discharge end of a primary nozzle Venturi tube which acts `t0 withdraw fuel from the carburetor float chamber or reservoir, the movable sleeve further serving in its movement .to control the size of the discharge opening into the mixing chamber from a vacuum' Venturi tube used for creatingan enhanced suction in the upper spaces of the carburetor iioat chamber or fuel reservoir. A

My invention is illustrated in the accompanying drawing, in'which Figure 1 is a vertical section, and Figure 2 is an elevation partly broken away taken 90 from lthat of Figure 1.

Referring to the drawing, in which like parts are' designated by like reference characters, the main housing 3 is attached to the intake manifold of an internal combustion engine, (not shown) .by means of a flange 4 provided inthe usual manner with bolt ile, and oneobject of' or screw holes. The housing 3 is preferably .of cast metal, shaped as illustrated to proopening 6 is the usual throttle 12, controlled- 'llhe by the lever 13 in the usual manner. seat 11 is centrally bored to receive the discharge end of a nozzle Venturi tube 15,

which extends about one-fourth of an inch above the face of the seat 11 along the axis of the movable tube 10.. Atmosphere is conducted to the external end of the nozzle,

Venturi tube 15 through a downwardly extending tubular portion 17 forming a part of the main casting, and also serving as a means for-holding the float chamber bowl 18 in place. Fuel is conducted to the nozzle openings 19 within the Venturi tube 15 through a duct 20, shown in Figure 2. A ioat 21 controls a float valve ,22, so as to admit fuel onl Whenthe fuel in the float chamber falls elow a predetermined level.

A'vacuum Venturi tube 25 vextends throu h the housing 4 at substantially rightang es to thebore of the passage 6, and terminates in the mixing chamber at a position substantially movable tube 10-when that tube isv in its normal position.l The external surface of the movable tube 10 is contoured at26, so that .for different positions .of the tube 10 along its axis it wil-l serve' to variably vrestrict the discharge end of the vacuum Venturi tube 25.." Thisvacuum Venturi tube has a very small throat, so that the air admitted throu h it will be much less than that necessary or the smallest engine demand. The tube 25 preferably has a pressed fit within the housmg 3, and has openings 27 which communicate by means of a passage 28 with the upper space of the float chamber. A cam 30, pivoted at 31 and held against a flat surface on the housingl 3 by means of a spring washer .32, is so shaped that by its on the line of the upper edge of the' rotation the entrance to the Venturi tube 25 registers with a passageway 351m the housing which leads to the space surrounding 'the movable tube 10. The purpose of this is to relieve the vacuum within the space surrounding the tube 10, so that suction within the discharge opening 6 will have less effect in raising the tube 10 off its seat 11, and thus cause a higher suction to be created 1n the mixing chamber of .the carburetor for enriching the mixture in starting. l

A mixture of fuel andair for idling purposes is conveyed from a position near the discharge ed of the nozzle Venturi tube 15 to a point on the engine side of the throttle 12 through a drilled passageway 40, in which is located anadjusting screw 41 by means of which the effective size of the passageway may be altered: A low level supply tank L13-is shown partially in section in Figure 2, it being understood that this tank will, in practice be located at some distance away from the carburetor, and will usually be located at the rear of the vehicle when the carburetor is used in connection with an` automobile engine.

In the operation ofthe device, because of the ample clearance between the sleeve 7 and the movable tube. 10, the suction of the `en-A gine will be effective within the chamber in which the spring 9 is located, and will, under normal conditions of operation, raise the movable tube 10 slightly off its seat 11 to admit a small amount `of air between the lower edge of the tube and its seat, the'opening through the nozzle 15 being so small that 'the air and fuel admitted at this point will not supply the engine even for its lowest idling demand. The suction within the mixing chamber under the lowest demand of the engine will, of course. be `controlled by the strength of the spring 9, and the weight withdraw fuel 'from the reservoir.

of the movable tube 10. These are preferably adjusted so that a suction equivalent to about 15 inches of gasoline in a manometer tube is required for liftinoA the tube 10 off its Seat 11. The' vacuum enhance this'suction, so that even for the idling condition of the motor the suction 'available at the throat of the vacuum Venturi tube is equivalent to about 40 inches of asoline in a manometer tube. This suction 1s available for lifting fuel from the low level supply `to the carburetor reservoir. Notwithstanding this hi ghl suction in the fuel reservoir, the nozzle Venturi tube 15 will rlhis is because the discharge end of the nozzle V e11- turi tube 15 is located within the reciprocating tube 10 at a point where the velocity of the air is made high by its passing around fthe enlargement 11V and through the 'restricted intake end of the tube 10. ".ll"

vcreased suction at the discharge end the nozzle Venturi `tube correspondingly increases the suction at the fuel inlet openings,

Venturi tube 25 serves tol which suction'by the design of the several `parts is made higher than that produced at tlie'throat of the vacuum Venturi tube 25. As the throttle 12 is opened to speed up the engine, and as the engine speed increases responsive thereto, the liow of a1r through the carburetor correspondingly increases. The static suction within the mixing chamber likewise increases, because it is controlled by the spring 9, which somewhat increases in pressureas it is collapsed. The velocity vsuction withinthe movable tube 10, however', increases very rapidly due to the very greatly increased How-of air, so that the quantity of fuel drawninfis substantially proportional to the quantity of air, thus maintaining a Substantially constant mixture. This mixturc, however, may be accurately adjusted by the contour of the outer Wall of the movable tube 10 at the position 26 so as to vary the amount of air entering through the Venturi tube 25, and, thus to create slight alterations in the float chamber suction to bring about the correct mixture. The shape of the contoured portion of the movable tube l() is experimentally determined, and once having been determined will b e the same in all carburetors of like capacity.

The'degree of richness of the mixture may be controlled, for example, for summer and winter driving, or for starting by rotating the cam 30 so as to change the degree of restriction at the entrance to the Venturi tube 25. l/Vhen the cam 'is rotated so as to entirely close lthis entrance, the mixture will be very greatly enriched, because under this condition the float chamber receives only the same vacuum as the mixing chamber. As the cam is moved to enlarge the entrance opening to the Venturi tube 25, the eectiveness of the Venturi tube 25 increases, and the vacuum in the float chamber correspondingly inlll() creases, thus decreasing the fuel feeding dif-v .y duction passage, a sleeve arranged to reciprocate longitudinally within said passage, an

abutment against which thev anterior open end of said lsleeve normally rests to close communication 'between atmosphere and the interior of said induction passage, said sleeve having an enlargement fitting the passage, one surface of said enlargement being subjected to atmospheric pressure whereby 'suc tion 'in the induction passage tends to raise said sleeve ofi of the abutment, a spring for normally holding said sleeve. against the abutment, a nozzle Venturi tube projecting through the abutment and having its delivery end projecting somewhat beyond the plane at which said sleevetrikes said abutment, fuel delivery means in said nozzle Venturi tube, a fuel chamber communicating with said means, a vacuum Venturi tube extending through the wall of the induction passage and` having its delivery end positioned opposite a lportionof said sleeve, a

duct for connecting the throat of said Vac-4 uum Venturi tube with the upper-space of the fuel reservoir for creating a suction therein for lifting fuel thereto, the said sleeve having a contoured outer surface for variably regulating the amount of air. drawn inthrough said vacuum Venturi tube.

42. In a carburetor, the combination with a casing, a chamber therein for connection with the intake of an induction motor, a nozzle Venturi tube having oneend exposed to atmosphere, and the other end extending into said chamber, an enlargement about the end; of said Venturi tube, an atmospheric communication surrounding said enlargement, a

` sleeve operating in said chamber and having connection between said Venturi tube and the upper part of said fuel reservoir controlled by movement of said sleeve for creating a suction therein for lifting fuel thereto.

'3. In a-carburetor, the combination with 'a casing, a chamber therein for connection.

with the intake of an induction .motor, a. nozzle Venturi tube having one end exposed to atmosphere, and; the other end extending into said chamber, an enlargement about the end of said Venturi tube; an atmospheric ,communication surrounding said enlargement,a sleeve operating 1n said chamber and having an end which (zo-operates with said enlargement to close a communication between atmosphere and said chamber, said sleeve being movable out of contact withv said enlargement under the influence of suc` tion in said chamber, the' air passing into' saidchamber between said enlargement and aff the end of said sleeve being directed past the.-A

end of said Venturi tube for creating an additional suction on said Venturi tube, a fuel reservoir eectively closed to atmosphere, a vacuum producing Venturi tube extending from atmosphere and discharging linto said chamber, a connection :from said Venturi tube to said fuel reservoir -for creating a suction therein for lifting fuel thereto, the inner end of said vacuum producingVenturi tube terminating inthe-region of the external surface of said sleeve, said sleeve being contoured to control thel discharge of air from the inner end of said Venturi tube,

whereby the suction in may be controlled.

In witness whereof,-I hereunto subscribe my n ame this 3rd dayl of October, 1922.

- FRED scHoENwoLF.

the fuel reservoir 

